1. Field of the Invention
This invention relates to a liquid jet head, a liquid jet head cartridge, and a liquid jet apparatus. More particularly, the invention relates to a liquid jet head formed by joining a discharge port member with an elemental base board having the elements on it for generating discharge energy for discharging liquid, a liquid jet head cartridge and a liquid jet apparatus which use such liquid jet head.
2. Related Background Art
As an ink jet recording head, there have hitherto been used, among others, a head which adopts piezoelectric elements as those generating discharge energy to creation pressure changes in the ink passages for discharging ink droplets by the utilization of the distortion of the piezoelectric elements, and a head which uses heat generating elements arranged in ink passages to create air bubbles by heating ink rapidly for discharging ink droplets. Of these heads, the so-called bubble jet recording head, wherein ink is discharged by heating it rapidly by use of the elements for generating heat, can be structured simply to make it possible to arrange many numbers of nozzles in a high density. Advantageously, therefore, this method enables a high speed recording in a high precision.
As a method of manufacturing the bubble jet recording head having many nozzles integrally formed in it, a heater board is prepared by arranging a thinly filmed heater and its wiring on the surface of a plate made of silicon or the like, and using it as the base board, a dry film is bonded on it. Then, after exposure and development, a ceiling board made of glass or the like is joined to it, and the discharge port unit is produced by cutting the integrated body thus fabricated. Also, there is, among others, a method in which the nozzle pattern is formed on the base board by use of a photosensitive resin. After covering it with resin, the integrated body thus prepared is cut to form the discharge port unit, and then, the photosensitive resin is removed for the formation of a head. Further, a method is adopted to make a discharge port member, in which grooved nozzles and discharge ports are formed by resin, and then, to press this member to be in contact with a base board to fabricate a head. It is widely used because the nozzles of a complicated configuration can be fabricated at a lower cost in accordance with this method. The method is remarkably superior and suitably applicable to its production on a large scale. This method is disclosed in the specification of Japanese Laid-Open Patent Application No. 2-192954.
As a structure to supply ink to many numbers of nozzles, methods are known, in which ink is supplied from behind the base board by providing through holes for the base board or in which ink is supplied from the end portion of the base board by arranging grooves for the base board or some others in addition to the method wherein the ink supply paths are arranged for a common liquid chamber formed on a base board together with nozzles. These methods are disclosed in the specifications of Japanese Utility Model Publication No. 3-10046, Japanese Utility Model Publication No. 2-26677, and Japanese Laid-Open Utility Model Application No. 61-166841.
For the method of manufacturing a recording head by preparing the discharge port member having the grooved nozzles formed by resin, and pressing it to be in contact with the base board for the formation of the head, it is important to arrange the discharge port member to be in close contact with the base board reliably. In the specification of Japanese Laid-Open Patent Application No. 2-192954, it is disclosed that the discharge port member is pressed to be in contact with the base board by use of a spring compressing it from the above. This method makes a close contact possible reliably, but it results in limiting the configuration of a recording head because of the required arrangement of a spring and others above the discharge port member.
For example, it is difficult to apply this method to a recording head of a type in which ink is discharged in the surface direction side of the base board. If it should be arranged just to mount the discharge port member having discharge ports and walls between adjacent nozzles on the base board, the pressure exerted between the adjacent nozzles tends to leak, and not only the discharging force is weakened, but also, a hindrance occurs due to cross talks. It is also difficult to bond them by use of adhesives because nozzles are extremely small. If contacting means such as a spring is arranged above the surface of the discharge port member, the quality of recording image is degraded since it is impossible to set the distance between the discharge ports and a recording medium close enough to obtain a recorded image of a good quality.
This invention is designed to solve these problems. It is an object of the invention to provide a liquid jet head for which the discharge port member and the base board can be closely in contact with each other reliably, the head configuration can be flexibly arranged, and the distance between the discharge ports and a recording medium can be set close enough.